Obesity can increase your chances of heart disease, diabetes, high blood pressure, stroke, osteoarthritis, cancer and gallstones - as well as cause depression and low self-esteem. Despite warnings, we seem to be getting fatter. Why is it happening, and how can we prevent it?

This article on obesity in the UK and obesity treatment is written by Sarah Dawson, a freelance journalist and regular contributor to Private Health UK.

Obesity is a serious issue facing our nation - and the western world - today. Levels have tripled in the past two decades in England and the government reports that a fifth of men and a quarter of women are now obese, with a staggering 24 million adults thought to be overweight or obese.

Perhaps more worrying is the increase in obesity in children - the proportion of obese children aged between six to fifteen years increased by around three and a half percent between 1996 and 2001 - and continues to grow. Most of us eat more than we need to, much of which is higher in calories than our bodies were originally designed to cope with.

Theories abound as to why we're becoming a nation of 'fatties'. It would be easy to blame the obesity epidemic on laziness, too much time spent horizontal on the sofa, and instead of cycling or running around in fields, children today are staying indoors to play computer games or be transfixed to the TV screen. Some say it's an energy imbalance - we're taking in more energy (food) than we're using because we're not getting enough exercise to burn it off. Equally, not eating the right types of food, a lack of education about healthy food, or even limited healthy food selections in supermarkets or local shops are other possible factors, as is an over-reliance on cars and the closing down of school playing fields. It doesn't help of course that sugary and fatty foods are fast, cheap, and generally more accessible than fresh fruit and vegetables if you're running short of time.

There seems to be no black and white explanation for the obesity crisis and certainly any or all of the above factors are perfectly feasible. Equally, scientists have recently discovered that more than half of the population carries a variant of a gene called FTO, which makes them more susceptible to gain weight, and research in October 2007 from Foresight (the government's science-based think tank) suggests that the nation's problem with weight-gain could be entirely out of our control. In its report, the company talks about the technological revolution of the 20th century being the cause of unavoidable weight gain because our bodies and biological make-up are out of synch with our surroundings.

Obesity thriving in UK

Regardless of the debate over cause, the obesity crisis continues to thrive - and statistics are very alarming. In a Health Survey of England in 2004, almost a quarter of adults were obese, in 2005 twenty two percent of English men and twenty four percent of women and nearly eighteen percent of boys and of girls aged between two and 15 in England were classified as obese. If current obesity growth rates continue, experts believe that some 60 percent of men, 50 percent of women and 25 percent of children in Britain could be obese by 2050.

There are plenty of negatives associated with obesity. Firstly, you place yourself at a higher risk of serious conditions like cancer and heart disease and type 2 diabetes. Secondly, too much body fat means you might also develop osteoarthritis, a general wear and tear of your joints. If that isn't enough, the health risks will doubtless be coupled with some psychological and emotional problems like depression, lack of confidence, low self esteem, and potentially social discrimination and prejudice.

According to the Department of Health, obesity is responsible for 9,000 premature deaths each year in England and it reduces life expectancy on average by nine years. On an economic level, the estimated cost of obesity to the NHS is approximately £1billion per year, with an additional £2.3b - £2.6b per year to the economy as a whole. Unless things change, experts predict that by 2010 the cost to the economy could be £3.6b per year.

Testing

If you store fat in the abdominal area (Apple shapes) experts believe you're more at risk of developing heart disease and diabetes, compared to those who store excess fat in the hips and thighs (Pear shapes). The Body Mass Index (BMI), a mathematical formula used by health professionals helps to establish whether a person is a healthy weight for their height, and a BMI reading of over 30 signifies 'obesity'. However, because muscle weighs more than fat, the BMI test isn't always accurate so the waist to hip ratio (which calculates the proportion of fat stored on your body around your waist and hips) can be a better obesity indicator. Measure your waist (around your tummy button), then your hips at their widest point (around the buttocks) and divide your waist measurement by your hip measurement to get your reading.

As a guideline, the World Health Organisation (WHO) says a BMI reading of between 25 and 29.9 indicates you're over the recommended weight for your height, a reading of between 30 and 39.9 means you're obese, and a reading over 40 means you're very obese. The BMI method is unreliable for determining a child's obesity as the reading will change as they grow, but the clinical definition of overweight and obesity in children is based on BMI percentile charts for boys and girls taken between the ages of two and 16 years. The National Institute for Health and Clinical Excellence (NICE) recommends tailored clinical intervention for children with a BMI at or above the 91st centile.

The National Audit Office (NAO) has predicted that one million less obese people in the country would mean 15,000 less people with coronary heart disease, 34,000 less people developing type 2 diabetes, and 99,000 less people with high blood pressure. But dieticians say that gimmicky diets aren't the answer and the government maintains there is no 'quick-fix' to tackle the crisis, which the Foresight report says could take 30 years to reverse. In order to overcome obesity, people need to follow a healthy, balanced, low-fat diet and get plenty of exercise. Education is obviously key for parents to set the right example to their children - as early as possible in their lives.